CA-31930: fix balloon handling for domain 0
CA-31930: fix balloon handling for domain 0

Make domain 0 look like all other domains wrt balloon handling:
* on system boot set memory/target to total_memory_pages (in KiB)
* on system boot set control/feature-balloon = 1

Remove the code which directly set the domain 0 memory target since this conflicts with the background ballooning code. Instead we use the API to call set_memory_dynamic_range on dom0.

Initially set the memory/target to total_memory_pages (in KiB obviously)

agimofcarmen/xen-api,robertbreker/xen-api,ravippandey/xen-api,jjd27/xen-api,agimofcarmen/xen-api,huizh/xen-api,anoobs/xen-api,huizh/xen-api,guard163/xen-api,koushikcgit/xen-api,jjd27/xen-api,robertbreker/xen-api,guard163/xen-api,huizh/xen-api,Frezzle/xen-api,anoobs/xen-api,srowe/xen-api,robertbreker/xen-api,anoobs/xen-api,euanh/xen-api,jjd27/xen-api,koushikcgit/xen-api,guard163/xen-api,thomassa/xen-api,salvocambria/xen-api,rafalmiel/xen-api,simonjbeaumont/xen-api,cheng--zhang/xen-api,simonjbeaumont/xen-api,anoobs/xen-api,ravippandey/xen-api,jjd27/xen-api,cheng--zhang/xen-api,srowe/xen-api,euanh/xen-api,koushikcgit/xen-api,cheng-z/xen-api,simonjbeaumont/xen-api,rafalmiel/xen-api,ravippandey/xen-api,simonjbeaumont/xen-api,rafalmiel/xen-api,ravippandey/xen-api,srowe/xen-api,vasilenkomike/xen-api,rafalmiel/xen-api,thomassa/xen-api,euanh/xen-api,koushikcgit/xen-api,vasilenkomike/xen-api,robertbreker/xen-api,euanh/xen-api,Frezzle/xen-api,thomassa/xen-api,vasilenkomike/xen-api,huizh/xen-api,jjd27/xen-api,huizh/xen-api,cheng-z/xen-api,djs55/xen-api,anoobs/xen-api,ravippandey/xen-api,cheng--zhang/xen-api,thomassa/xen-api,cheng-z/xen-api,rafalmiel/xen-api,djs55/xen-api,rafalmiel/xen-api,vasilenkomike/xen-api,agimofcarmen/xen-api,vasilenkomike/xen-api,robertbreker/xen-api,salvocambria/xen-api,cheng--zhang/xen-api,guard163/xen-api,koushikcgit/xen-api,cheng-z/xen-api,djs55/xen-api,cheng-z/xen-api,huizh/xen-api,Frezzle/xen-api,salvocambria/xen-api,cheng--zhang/xen-api,Frezzle/xen-api,Frezzle/xen-api,ravippandey/xen-api,salvocambria/xen-api,guard163/xen-api,srowe/xen-api,cheng--zhang/xen-api,koushikcgit/xen-api,anoobs/xen-api,agimofcarmen/xen-api,jjd27/xen-api,thomassa/xen-api,robertbreker/xen-api,djs55/xen-api,euanh/xen-api,djs55/xen-api,salvocambria/xen-api,srowe/xen-api,djs55/xen-api,salvocambria/xen-api,simonjbeaumont/xen-api,thomassa/xen-api,simonjbeaumont/xen-api,cheng--zhang/xen-api,euanh/xen-api,agimofcarmen/xen-api,cheng-z/xen-api,guard163/xen-api,agimofcarmen/xen-api,vasilenkomike/xen-api,cheng-z/xen-api